Electric furnace.



fire resistant material.

UNITED STATES PATENT OFFICE.-

INGENUIN HECHENBLEIKNER, OF CHARLOTTE, NORTH CAROLINA, ASSIGNOR TOSOUTHERN ELECTED-CHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORA-- TIONOF NEW JERSEY.

ELECTRIO FURNACE.

Specification of Letters Patent.

Patented Oct. 31, 1916.

Application filed February 7, 1914. Serial No. 817,369.

To all whom it may concern:

Be it known that I, INGENUIN HEOHEN- BLEIKNER, subject of the Emperor ofAustria-Hungary, and resident of Charlotte, in the county of Mecklenburgand State of North Carolina, have invented certain new and usefulImprovements in Electric Furnaces, of which the following is aspecification.

This invention relates to electric furnaces and particularly to suchfurnaces as may be used in the manufacture of phosphorus vapors andphosphoric acid by heating phosphate rock with silicious material andcarbon.

The objects of the invention are to utilize the heat of the furnacegases to uniformly preheat-the charge and to avoid overheating of thebrick work, electrodes and other parts ence indicate corresponding partsin all the figures.

Referring to the drawings,- A- represents the body portion of thefurnace, B the stack, and C the tapered frustoconical portion connectingthe body portion with the stack. These parts will be constructed ofsuitable I have shown a sheet metal casing D having a lining E of, firebrick. j

The body portion of the furnace is provided with a water jacket Fsurrounding the sides and bottom thereof and conveniently constructed ofsheet metal reinforced with suitable angle irons and channels. Therefrigerant, preferably water, is introduced through suitable pipes 10at the bottom and withdrawn through other pipes 11 at the top. The innerportion 20 of the water jacket is connected at the top only with theouter portion 21 whereby it may be free to expand of one jacketembracing the larger end of the other. The inner jacket is held inposition by suitable means, such as a strap 18 on the outer jacket. Itwill be seen that the inner tap jacket 15 may be readily removed andreplaced when it becomes worn out or clogged. Both of the jackets 14 and15 are embedded in the fire brick lining E.

The electrodes G and H of carbon or graphite extend through the taperedportion C of the furnace and each is surrounded as it passes through thepoint where it ,enters the furnace wall with a water cooled jacket Iwhich also serves as a packing box. Each of the jackets 5 is embedded inan extension 26 formed in the side of the tapered portion and may bemade from a suitable casting provided with a water inlet pipe 27 andoutlet pipe 28. The jacket I is further formed around the electrode withable packing 30, preferably asbestos. To

avoid any current leakage, the water jackets do not form a connectedring around the electrodes, but are separated at 30 by a break in theannulus to leave an isolated space between the ends.

The electrodes are adjustable with respect to the jacket I, and are alsoformed with suitable current connectors, preferably of a water cooledtype, the construction of which does not form part of the presentinvention. The electrodes are also adjusted and fed by any suitable orwell known means. It will be observed the jackets I extend only part waythrough the fire brick lining, whereby they are protected on the innerside from the heat and chemical reaction within the furnace.

The raw material is fed to the stack B through a suitable charging belld and the volatile products of the reactions in the furnace arewithdrawn through an outlet eon- -duit K, which leads laterally from oneside of the top of the stack.

It will be observed that the tapered portion of the furnace is aconsiderable distance above the electrodes and above the reaction zone,whereby the gases liberated by the re action will preheat that portionof the charge which is in the tapered portion and stack of the furnace.

It will be observed that as the heat of the furnace gases is'reduced thearea over which they are distributed is also reduced to correspond,whereby a' uniform degree of heating is obtained and the flow of thefurnace gases not restricted by the reduction of area. It will also beobserved as the electrodes extend through the smooth inclined bodyportion of the furnace wall no pocket will be formed above theelectrodes in which hot gases might collect to overheat either the.electrodes or the wall of the furnace.

llhis tapered shape also reduces the pressure on the carbon as theportion of the electrodes within the furnace is not subject to theentire weight of the charge in the stack. The furnace is particularlyadapted for use in a process for the manufacture of phosphoric acid inwhich the material to be furnaced consists of a mixture of naturalphosphate rock, silicious material and carbon, and the furnace gasesconsist of phosphorus vapor, carbon monoxid and phosphoric acid, whichfurnace gases assist in preheating the charge in the manner alreadyexplained.

It is essential in this process in the manufacturing of phosphorusiorphosphoric acid, that the temperature shall be well regulated and theintense heat of the electric are so applied to avoid a local overheatingof the charge or of the slag. Overheating of the charge or slag willcause a distillation of not only phosphorus but will also produce adistillation of silicon compounds.

Silicon and silicon compounds are generally the cause of killing thephosphorus, or, in case the phosphorus is afterward oxidized for themanufacture of phosphoric acid, said phosphoric acid forms waterinsoluble, commercially worthless compounds containing SiO and P 0 Toprevent these disadvantages in the process the typical design of thefurnace shown is the most important feature. Tests have shown that inthe case of this furnace the charge moves regularly and under a steadypressure downward between and around the electrodes. In this way theonce melted and reduced slag is removed quickly out of the dangerous arczone before overheating can take place. Fresh material replacing quicklythe melted slag prevents the formation of hollow spaces between theelectrodes and charge, and at the same time prevents overheating ofmaterial and distillation of silicon and silicon compounds; It makes nodifference whether the material be powdered, ranulated or briqueted, ifthe melting of the material be as described above since no distillationof harmful compounds takes place. The break in the water jacket aroundthe electrode already described is found to be particularly useful foran alternating current.

In the practical operation of the furnace the calcium silicate slag willflow continu ously through the upper tap holes 12, while any heaviermaterial, such as iron may from time to time be taken out through thehole '13. @wing to the high conductivity of the hot melted slag andmetallic water jacket, it is necessary that the furnace should bethoroughly insulated from the ground.

Having thus described my invention, what I claim is:

1. An electric furnace having an expansible water jacket formed withdisconnected parts inclosing the sides and bottom in a continuousmanner.

2. An electric furnace comprising a body portion, a water jacket thereonformed with disconnected parts, an uncooled masonry tapered portionformed with integral masonry extensions on the sides, electrodesextending through the extensions, and water jackets for the electrodesextending partially in the extensions and being supported thereby.

3. An electric furnace comprising a cylindrical bottom portion in whichthe greater part of the reaction is adapted to take place, formed withseparated tap holes, a tapered portion above the cylindrical portion andhaving a wall tapering uniformly inwardly from the same, electrodesextending through the tapered portions and projecting downwardly intothe body portion, and a top cylindrical portion formed with a laterallyextending conduit integral therewith.

4:. An electric furnace comprising a body portion, a masonry taperedfrusto-conical portion formed with integral extensions on the sides, astack above the tapered portion and electrodes extending through theextensions on the tapered portion and extending downwardly into the bodyportion.

6. In an electric furnace, at body portion, ed to extend completelyaround the same, 15 a water jacket surrounding the sides and 'save for aSingle gap which .forms an insubottom thereof and constructed of vsheetlating space between the ends. metal reinforced with angle irons andchan- Signed at 141 Broadway, in the county of 5 nels, the inner portionof the Water jacket New York andState of New York this 4th beingconnected at the top only with the day of February, A. D. 1914:.

outer portion whereby it may be free. to ex- INGENUIN HEGHENBLEIKNER.pand and contract. Witnesses:

7. In an electric furnace, a, water jacket RUssEL S. SMART,

1 adapted to surround an electrode and adapt- HARRY W. THoMPsoN.

